How to write a progam to creation and display of elements in both forward and reverse direction in a doubly linked list in C Programming Language ?
https://en.wikipedia.org/wiki/Doubly_linked_list
Solution:
/* Creation and display of elements in both forward and reverse direction in a doubly linked list */
#include <stdio.h>
#include <stdlib.h>
struct node* create(struct node *, struct node **, int);
void display(struct node*);
void displays(struct node*, struct node*);
struct node
{
int data;
struct node *rptr, *lptr;
};
int main()
{
struct node *head, *tail;
head= NULL;
tail= NULL;
int i, n, value;
printf("\nEnter the number of values u want to enter\n");
scanf("%d", &n);
for(i=0; i<n; i++)
{
printf("\nEnter the number you want to enter\n");
scanf("%d",&value);
head=create(head, &tail, value);
}
printf("\nThe data in forward direction is printed below\n");
display(head);
printf("\nThe data in backward direction is printed below\n");
displays(tail, head);
}
struct node* create(struct node *head1, struct node **tail1, int dat)
{
struct node* newnode, *temp;
newnode= (struct node*) malloc (sizeof(struct node));
newnode->data=dat;
newnode->rptr= newnode->lptr= NULL;
if(head1 == NULL)
{
newnode->lptr=newnode->rptr=NULL;
head1=newnode;
}
temp=head1;
while(temp->rptr != NULL)
temp=temp->rptr;
temp->rptr= newnode;
newnode->lptr=temp;
newnode->rptr=NULL;
*tail1 = newnode;
temp=temp->rptr;
return head1;
}
void display(struct node* head)
{
while(head!= NULL)
{
printf("%d\n",head->data);
head=head->rptr;
}
}
void displays(struct node *tail, struct node *head)
{
while (tail != head)
{
printf("%d\n", tail->data);
tail=tail->lptr;
}
if(tail == head)
printf("%d\n", tail->data);
}
